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Lean Construction: From Theory to Implementation

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Describes the difference between Lean Manufacturing and Lean Construction and Moving from Lean Manufacturing to Lean Construction

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Lean Construction: From Theory to Implementation

  1. 1. Lean Construction: From Theory to Implementation Ideas for today and tomorrow F Antonius P. Bramono * pbramono@gmail.com
  2. 2. Construction vs Manufacturing VS
  3. 3. • In manufacturing, finished goods generally can be moved as a whole to retailers or end customers. • Construction, on the other hand, deals with larger units that cannot be transported.
  4. 4. Additionally, the construction industry has three other features that distinguish it from manufacturing: Onsite production, one-of- a-kind projects, and complexity
  5. 5. Construction is site-position manufacturing, as opposed to fixed- position manufacturing, which applies to ship and airplane manufacturing & in which the product can be moved after assembly On-Site Production
  6. 6. In construction, installation and erection are the activities that most increase the value of the product. The contractor must ensure that all components assembled on site meet high-quality standards that are greatly influenced by specific site conditions
  7. 7. Normally manufacturing takes advantage of specialized equipment to make standardized units, allowing only a limited level of customization by retailers One-of-a-Kind Production
  8. 8. The image part with relationship ID rId2 was not found in the file. In construction, customers play a key role throughout the project cycle. Under guidance from the designer, customers define their product explicitly through the bid package or contract. The owner or the owner’s representative can modify the requirements and details of the contract by addenda (before bids are opened) or change orders (once the bid is closed)
  9. 9. In manufacturing, many components from different subassemblies can be easily managed because suppliers are selected early in the design phase. Specialized facilities with suitable technology and layout ensure the reliable flow of the product. With repetition, this supply network eventually becomes manageable and optimized Complexity
  10. 10. The image part with relationship ID rId2 was not found in the file. In contrast, in construction, the completion of activities is highly interrelated & complicated. Construction projects are characteristically complex, unique, dynamic systems that must rely on an initial design that involves a number of subassemblies with variable specifications.
  11. 11. Being an on-site production, the installation of those subassemblies is constrained by the interacting and overlapping activities of different contractors, making it more difficult to meet a fixed schedule.
  12. 12. The manufacturing process makes it possible to reduce uncertainty by increasing control over the process itself. A steady state is desirable in order to increase efficiency through repetition Uncertainty
  13. 13. The image part with relationship ID rId2 was not found in the file. In construction projects, significant uncertainty exists throughout the project. Weather conditions, soil conditions, owner changes, and the interaction between multiple operations can produce unique circumstances, which could be as critical as the planned activities and have a significant impact on project cost
  14. 14. Quality in manufacturing is related more closely to process control than to product conformance. Common tasks are defect prevention, monitoring, & intervention. Rework is generally avoided, and in some cases, parts are discarded rather than reprocessed Quality Control Process
  15. 15. In contrast, quality in construction primarily related to product conformance. Specifications & drawings determine quality standards, & quality assurance is the joint effort of the construction company & the owner to meet safety requirements, environmental considerations, and conformance with applicable regulations. Rework is a common practice because only one final product will be delivered
  16. 16. Supply in manufacturing is an order-driven activity that is synchronized through material handling systems. The operations sequence in manufacturing is determined during the product design phase, and changes are limited by the determined layout. Supply Process
  17. 17. Supply in construction is schedule driven because the process span is longer & the sequence of tasks can be modified, if required, by unforeseen exceptions. The construction supply chain is main contractor-client based.
  18. 18. Subcontracting can account for most of the value of the project, and because project activities are totally interrelated, the relationship between subcontractors and the general contractor demands much cooperation and transparency.
  19. 19. The lean enterprise concept comprises a variety of production systems that share certain principles such as 5S, waste minimization, responsiveness to change, just-in-time, effective relationships within the value stream, continuous improvement, & quality from the beginning The Lean Enterprise Philosophy
  20. 20. The lean organization defines the activities on which the system focuses; to design, supply, and manufacturing as the core activities of the lean organization
  21. 21. Toyota has developed the techniques that support the principles of lean production by the Toyota Production System (TPS) as a combination of methods with consistent goals: cost reduction, quality assurance, and respect for humanity to ensure sustainable growth Techniques in Lean Manufacturing
  22. 22. There are four main elements identified in TPS: Just-In-Time (JIT), Jidoka, workforce flexibility, and creative thinking.
  23. 23. Just-in-time is based on the concept that inventories are not valuable and should be regarded as waste; accordingly, units should be available only when required. 3 methods are associated with just-in-time. 1. Just-In-Time (JIT)
  24. 24. 1. The Kanban (Japanese for “card” or “sign”) system is used to minimize inventories according to backward requests that flow through cards, baskets, or digital signals
  25. 25. 2. Heijunka ensures that fluctuation in demand can be met by the right sequence of production in minimum batches
  26. 26. 3. SMED (Single-Minute Exchange of Dies) is a system for dramatically reducing the time it takes to complete equipment changeovers. The essence of the SMED system is to convert as many changeover steps as possible to “external” (performed while the equipment is running), and to simplify and streamline the remaining steps.
  27. 27. Jidoka describes as "intelligent automation" or "automation with a human touch“, a mechanism in a lean manufacturing process that helps a worker avoid (yokeru) mistakes (poka). Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur. 2. Jidoka
  28. 28. Maintaining a flexible workforce allows a company to match its labor requirements with the fluctuating level of demand for its product. 3. Workforce Flexibility
  29. 29. With a flexible machine arrangement, it is possible to rotate positions in the production line and adjust the size of the crew to the pace required.
  30. 30. Only with well-defined operations can the crew attend multiple machines reliably. Machine operation should also be planned through preventive maintenance activities.
  31. 31. Creative thinking offers continuous improvement through feedback and supports the continual improvement of a production line’s daily tasks. 4. Creative Thinking
  32. 32. Problem-solving skills prevent defects from recurring. Teamwork empowers workers with control over the operation and allows for task rotation.
  33. 33. Moving from Lean Manufacturing to Lean Construction
  34. 34. In lean manufacturing, the impact of fluctuating demand levels controlled by optimizing the sequence of products with minimum batch sizes are reduced, demand fluctuations can be managed by making small adjustments to the production volume and the resources allocated. 1. Flow Variability
  35. 35. Techniques associated with production leveling are product sequence scheduling, flexible standard operations, multifunctional layout design, and total preventive maintenance.
  36. 36. Flow variability greatly influences lean construction practices because the late completion of one trade can affect the overall completion time of a project.
  37. 37. “Last planner” is a technique that supports the realization of plans in a timely manners. Last planners are the people accountable for the completion of individual assignments at the operational level.
  38. 38. The last planner process starts with the reverse phase schedule (RPS), i.e., a detailed work plan specifying hand-offs between trades for each phase.
  39. 39. Autonomation (Jidoka) is the notion that immediate action should be taken to prevent defects at the source so that they do not flow through the process. 2. Process Variability
  40. 40. In lean manufacturing, visual inspection allows workers the autonomy to control their own machines so that when they identify defective parts, they can stop the process to identify the root cause.
  41. 41. Fail-safe (Poka-yoke) devices are used to automatically prevent defects from going to the next process.
  42. 42. Because defects are difficult to find before installation, quality in construction has traditionally been focused on conformance. Lean construction concentrates efforts on defect prevention.
  43. 43. The image part with relationship ID rId13 was not found in the file. Failsafe actions can be implemented on a job site to ensure first-time quality compliance on all assignments.
  44. 44. The image part with relationship ID rId13 was not found in the file. In lean manufacturing, any resource that does not contribute to better performance is regarded as waste that should be eliminated from the system. The 5S’s can be used to identify waste, eliminated and make transparency in plants. 3. Transparency
  45. 45. The image part with relationship ID rId13 was not found in the file. In construction, the 5S’s allow for a transparent job site, at which materials flow efficiently between warehouses and specific jobs in the field. Since construction has mobile workstations, increased visualization can help identify the work flow and create awareness of action plans on a job site.
  46. 46. The image part with relationship ID rId13 was not found in the file. Continuous improvement cannot be associated with a specific technique. In fact, all techniques are set to drive continuous improvement via problem solving & creative thinking. However, in lean manufacturing, quality circles provide an opportunity for workers to actively participate in process improvement. 4. Continuous Improvement
  47. 47. The image part with relationship ID rId13 was not found in the file. These teams meet periodically to propose ideas for the most visible problems in the workplace. Quality, maintenance, cost reduction, and safety issues can be worked out by the teams to provide potential solutions for future activities.
  48. 48. The image part with relationship ID rId13 was not found in the file. The benefits of the quality circles are not only the implemented ideas but also the learning process that workers experience.
  49. 49. The image part with relationship ID rId13 was not found in the file. Operations are examined in detail, bringing ideas and suggestions to explore alternative ways of doing the work. The PDCA (plan, do, check, and act) cycle is used to develop the first-run study.
  50. 50. The image part with relationship ID rId13 was not found in the file. First, one “plans” a work process to study, analyzes the process steps, and brainstorms how to eliminate unneeded steps. To “do,” one tests new ideas on the first run. To “check,” what actually happens is described & measured. To “act,” the team is to reconvened, and teammates communicate the improved method as the standard to meet.
  51. 51. The image part with relationship ID rId13 was not found in the file. To ensure continuous improvement, the team’s capabilities must be best used to develop both individual and joint contributions.

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